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Org Biomol Chem. 2008 Nov 21;6(22):4134-41. doi: 10.1039/b811234g. Epub 2008 Sep 16.

A cyclodecapeptide ligand to vitamin B12.

Author information

1
Département de Chimie Moléculaire-UMR-CNRS 5250 & ICMG FR 2607, Université Joseph Fourier, BP 51, 38041, Grenoble Cedex 9, France.

Abstract

Libraries of cyclic decapeptides were screened with vitamin B(12) derivatives to give cyclic peptide ligands incorporating histidine and cysteine as coordinating residues and negatively charged amino acids. Two hits, cyclo-(HisAspGluProGlyIleAlaThrProdGln) and cyclo-(ValAspGluProGlyGluAspCysProdGln) were resynthesized in good yields for solution experiments. The peptides bind aquocobalamin with coordination of His or Cys to the cobalt with high affinities (K(a) approximately 10(5) M(-1)). Additional interactions between the peptide side chains and the vitamin B(12) corrin moiety were determined by studying the (1)H NMR solution structure. The cyclopeptide-cobalamin complex with the histidine residue showed enhanced stability towards cyanide exchange, demonstrating the shielding effect of the ligand on the metal center.

PMID:
18972044
DOI:
10.1039/b811234g
[Indexed for MEDLINE]

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